<h2>Shebang</h2>
<pre><code>#!/bin/bash</code></pre>

<h2>Comments</h2>
<pre><code># This is a comment</code></pre>

<h2>Strings</h2>
<pre><code>STRING="Hello World"
'Single and
multi-line strings are supported.'
"Single and
multi-line strings are supported."
cat &lt;&lt; EOF
Here-Documents
are also supported
EOF</code></pre>

<h2>Variables</h2>
<pre><code>echo $STRING
args=("$@")
echo ${args[0]} ${args[1]} ${args[2]}</code></pre>

<h2>Keywords</h2>
<pre><code>for (( i=0;i<$ELEMENTS;i++)); do
	echo ${ARRAY[${i}]}
done
while read LINE; do
    ARRAY[$count]=$LINE
    ((count++))
done
if [ -d $directory ]; then
	echo "Directory exists"
else
	echo "Directory does not exists"
fi
</code></pre>

<h2>Some well-known commands</h2>
<pre><code>crontab -l -u USER | grep -v 'YOUR JOB COMMAND or PATTERN' | crontab -u USER -

groups user1 user2|cut -d: -f2|xargs -n1|sort|uniq -d

wget -q -O - http://www.example.com/automation/remotescript.sh | bash /dev/stdin parameter1 parameter2

sudo dpkg -i vagrant_1.7.2_x86_64.deb

git pull origin master

sudo gpg --refresh-keys; sudo apt-key update; sudo rm -rf /var/lib/apt/{lists,lists.old}; sudo mkdir -p /var/lib/apt/lists/partial; sudo apt-get clean all; sudo apt-get update</code></pre>